Title of Invention	"AN IMPROVED PROCESS FOR THE PRODUCTION OF HIGH STRENGTH AND HIGH WEAR RESISTANT AL-FE-V-SI ALLOYS"
Abstract	This invention relates to an improved process for the production of high strength and high war resistant Al-Fe-V-Si alloys.This alloy is useful for the industries engaged in production of high strength wear resistant aluminum alloys which used in aerospace, transport and other engineering sectors. The process of present invention makes use of melting and alloying in a fumace. Castings are made in die casting or in permanent mould for ensuring a cooling rate 10-50°C/s, which is common in foundry practices. The microstructure of the cast materials reveals massive ten-armed star shaped particles with composition similar to Al3Fe with some amount of V and Si along with other interdendritic Al-Fe-silicide phases. These star shaped particles may act as notches, which are deleterious to the toughness of the materials. Moreover, the chunky star shaped particles prevent proper feeding of the casting which results in micro porosity in castings.

Title of Invention

"AN IMPROVED PROCESS FOR THE PRODUCTION OF HIGH STRENGTH AND HIGH WEAR RESISTANT AL-FE-V-SI ALLOYS"

Abstract

This invention relates to an improved process for the production of high strength and high war resistant Al-Fe-V-Si alloys.This alloy is useful for the industries engaged in production of high strength wear resistant aluminum alloys which used in aerospace, transport and other engineering sectors. The process of present invention makes use of melting and alloying in a fumace. Castings are made in die casting or in permanent mould for ensuring a cooling rate 10-50°C/s, which is common in foundry practices. The microstructure of the cast materials reveals massive ten-armed star shaped particles with composition similar to Al3Fe with some amount of V and Si along with other interdendritic Al-Fe-silicide phases. These star shaped particles may act as notches, which are deleterious to the toughness of the materials. Moreover, the chunky star shaped particles prevent proper feeding of the casting which results in micro porosity in castings.

Full Text	This invention relates to an improved process fix the production or high strength and high wear resistant Al-Fe-V-Si alloys. The present invention will be useful for the industries engaged in production of high strength wear resistant aluminium alloys which are widely used in aerospace, transport and other engineering sectors. In the general melting and casting process, the wide differences of densities and melting points of Al, Fe, V and Si couple with low diffusivity of Fe, V in Al pose problems in producing cast homogeneous structure. So, the Al-Fe-V-Si alloys are generally produced and shaped through a costly technique of rapid solidification - powder compacting - extrusion/ rolling route. As a prior art the rapid solidification processes, namely, atomizalion and tnelt spinning are used lo obtain rapidly solidified alloy powders or ribbons respectively. In atomization process the molten alloy is impacted by a high energy fluid for obtaining powders. The powders are cold pressed, degassed followed by hot consolidation. (E.J.Lavemia, J.D.Ayers, T.S.Srivatsan, International Materials Review, vol.37, No.l, (1992), 1-44). Then it is hot worked for obtaining final product. The melt spinning process employed a high pressure shock wave of gas to propel a small droplet of melt against a clean rotating metal wheel to produce a brittle ribbon or thin sheet. The ribbons are pulverised to obtain powder. The powders may be cold pressed and sintered or consolidated and heal treated (E.J.Lavemia, J.D.Ayers, T.S.Srivatsan, International Materials Review, vol.37, No. 1, (1992), 1-44). Then it is extruded or rolled to make the material for final product. Rapid solidification technique however, capital incentive and requires high skill of operation because: (i) the cooling rate is very high (105 to 106) which is difficult to achieve unless huge capital cost equipment is used, (ii) the powders / ribbons so obtained are not of uniform size leading to deterioration of mechanical properties, (iii) the steps of consolidation of the rapidly solidified alloy powders/ melt spin ribbons and processes to shapes give additional cost to the technique.(iv) the product capacity is limited to a small size only because the ribbon or powder so obtained are compacted or sintered to a small capacity for obtaining homogeneous structure These necessitated R & D effbrts for development of Al-Fe-V-Si alloy in cast route whose mechanical properties are comparable with those of identical alloy made by the known process as mentioned above. The process of present invention makes use of melting and alloying in a furnace. Castings are made in die casting or in permanent mould for ensuring a cooling rate 10°-50°C/s, which is common in foundry practices. The microstructure of the cast materials reveals massive ten-anned star shaped particles with composition similar to Al3Fe with some amount of V and Si along with other intei dendritic Al-Fe-silicide phases. These star shaped particles may act as notches, which are deleterious to the toughness of the materials. Moreover, the chunky star shaped particles prevent proper feeding of the casting which results in microporosity in castings. Thus, the mechanical properties of the samples deteriorate to a greater extent. This invention aims to modify blocky primary inlermelallic phases as well as interdendritic silicide phases by treating the melt with elemental magnesium or magnesium beating master alloys to gel a structure containing uniform distribution of intemietallic phases. The uniform distribution of primary and interdendritic phases are obtained with addition of magnesium or magnesium beating master alloys because the moiphology of the inteiface changes, so more nuclei is created. It also breaks the dendrite of the primary particles leading to structural change and fine particles, The main object of the present invention is to establish melting treatment process for the production of cast and mechanically worked high strength and high wear resistant Al-Fe-V-Si alloys leading to superior properties. Accordingly, the present invention provides an improved process fro the production of high strength and high wear resistant Al-Fe-V-Si alloys which comprises: i) melting pure aluminum, Al-Fe-V, Al-Si master alloys at a temperature in the range of 800 to 1000°C to obtain a melt of Al-Fe-V-Si in the following compositional ranges: Fe = 8 to 10 wt%, V=0.8 to 1.0wt%, Si=0.8 to 1.7 wt% and balance Al, ii) degassing the said melt by known method, iii) adding magnesium in the range of 0.05-1% to the degassed melt, iv) pouring the resultant melt in a dia/mould to obtain a casting followed by cooling, v) heating the casting obtained to a temperature in the range of 350-500°C, followed by hot rolling to obtain high strength and high wear resistant Al-Fe-V-Si alloys. In an embodiment of the present invention the pure aluminum used may be of 99.6% purity. In another embodiment of the present invention the degassing of the melt may be effected using known method such as adding known flux or argon gas. In still another embodiment of the present invention the magnesium used may be such as pure magnesium of 99.8% purity. In yet another embodiment of the present invention the magnesium used may be magnesium bearing master alloys such as Al-Mg, Fe-Si-Mg, Ni-Mg master alloys. In another embodiment of the present invention the magnesium bearing master alloys used may be selected from Al-10-20%Mg, Fe-Si-9-20%Mg, Ni-10-20%Mg The following example are given by way of illustration and should not be construed to limit the scope of invention. Example 1 2 kg of Al-8.0% Fe-0.8% V -0.9% Si alloy was melted in a clay bonded graphite crucible in electric resistance furnace. The alloy was modified with 0.5% pure magnesium. The materials taken were metallic silicon 18 gm, ferro-vanadium 25 gm, aluminium- 30% iron master alloy 510 gm. 0.5% pure magnesium (10 gm) was used to modify the alloy. After melting the melt was kept at a temperature of 860° C for complete dissolution of solute elements. Degassing treatment was done by pure argon, followed by magnesium treatment at temperature of 850oC. The mell was poured in metallic mould of 30 mm diameter. The specimen so obtained was evaluated for microstructure and mechanical properties The microstructure was uniform distribution of primary and interdendritic phases in aluminium matrix. The mechanical properties were reported in Table 1 Table 1 Mechanical properties of unmodified and modified alloys (Table Removed)Example 2 2 kg nf Al-8 0% Fe-0 8% V -0 9% ,Si alloy was melted in a clay bonded graphite crucible in electric resistance furnace. The melt was modified with 10% of aluminium-20% magnesium master alloy 20 gm of master alloy was taken The microstmeture obtained by this modification was more uniform distribution of primary and interdendritic phases The particle size distribution was finer than pure magnesium treatment The mechanical properties were shown in Table 1 The alloys were further hot rolled at a temperature of 350°C and deformation was 75% The mechanical properties was shown in Table 2. Table 2 Mechanical properties of hot worked alloys, hot rolled at 350°C, reduction 75% (Table Removed)Example 3 3 kg of aluminium -83% iron - 0 8% vanadium-0 9% silicon alloy was melled in a clay bonded graphite crucible in electric resistance furnace The alloy was modified with 1.0% of nickel - 20% magnesium. The materials taken were silicon 30 gm, ferro- vanadium 38 gm, aluminium - 10% iron master alloy 780 gm nickel- magnesium 30 gm After degassing the melt the alloy was modified. Prior to modification the master alloy was preheated to 250°C. The microstructure obtained by modification was more unifonn distribution of primmy and interdendritic pliases The paiticle size distribution was finer than pure magnesium treatment The mechanical properties were shown in Table 1 The alloys were further hot rolled at a temperature of 350T and deformation was 75%. The mechanical properties was shown in Table 2 By the process of present invention a cast high strength and high wear resistant Al-Fe-V-Si alloy having unifonn distribution of primary phases in the form of ciiboidal, hexagonal, rectangular shape and refined interdendritic phase has been achieved The properties of the alloy produced by the process of present invention are comparable to those obtained through known process The mechanical properties also .improved considerably after hot working as shown in Table 1 and 2 above. The main advantages of present invention are; (i) The steps involved for making the alloy are simple, economic and takes much shorter time than the existing process of rapid solidification route (ii) Costly equipment for making powders/ ribbons are avoided in the process of present invention (iii) Cooling rate required is much lesser than the existing process of rapid solidification (iv) The process of present invention has achieved uniform distribution of refined primary intermetallic and interdendritic silicide phases (v) The cast and mechanically worked products produced by the present invention exhibit comparable mechanical properties to those produced by rapid solidification processing route (vi) The cost of production of the present invention is much cheaper than the existing process of rapid solidification route. We Claim: 1. An improved process for the production of high strength and high wear resistant Al-Fe-V-Si alloys which comprises: i) melting pure aluminum, Al-Fe-V, Al-Si master alloys at a temperature in the range of 800 to 1000°C to obtain a melt of Al-Fe-V-Si in the following compositional ranges: Fe = 8 to 10 wt%, V=0.8 to 1.0 wt%, Si=0.8 to 1.7 wt% and balance Al, ii) degassing the said melt by known method, iii) adding magnesium in the range of 0.05-1 % to the degassed melt, iv) pouring the resultant melt in a dia/mould to obtain a casting followed by cooling, v) heating the casting obtained to a temperature in the range of 350-500°C, followed by hot rolling to obtain high strength and high wear resistant Al-Fe-V-Si alloys. 2. An improved process as claimed in claim 1 where in the pure aluminum used may be of 99.6% purity. 3. An improved process as claimed in claims 1-2, wherein the degassing of the melt is effected using known method such as adding known flux or argon gas. 4. An improved process as claimed in claims 1-3 wherein the magnesium used is such as pure magnesium of 99.8% purity. 5. An improved process as claimed in claims 1-4 wherein the magnesium used is magnesium bearing master alloys such as Al-Mg, Fe-Si-Mg, Ni-Mg. 6. An improved process as claimed in claims 1-5 wherein the magnesium bearing master alloys used is selected from Al-10 to 20% Mg, Fe-Si-9 to 20% Mg, Ni-10 to 20% Mg. 7. An improved process for the production of high strength and high wear resistant Al-Fe-V-Si alloys substantially as herein describe with reference to the examples.

Full Text

This invention relates to an improved process fix the production or high strength and high wear resistant Al-Fe-V-Si alloys.
The present invention will be useful for the industries engaged in production of high strength wear resistant aluminium alloys which are widely used in aerospace, transport and other engineering sectors.
In the general melting and casting process, the wide differences of densities and melting points of Al, Fe, V and Si couple with low diffusivity of Fe, V in Al pose problems in producing cast homogeneous structure. So, the Al-Fe-V-Si alloys are generally produced and shaped through a costly technique of rapid solidification - powder compacting - extrusion/ rolling route. As a prior art the rapid solidification processes, namely, atomizalion and tnelt spinning are used lo obtain rapidly solidified alloy powders or ribbons respectively.
In atomization process the molten alloy is impacted by a high energy fluid for obtaining powders. The powders are cold pressed, degassed followed by hot consolidation. (E.J.Lavemia, J.D.Ayers, T.S.Srivatsan, International Materials Review, vol.37, No.l, (1992), 1-44). Then it is hot worked for obtaining final product.
The melt spinning process employed a high pressure shock wave of gas to propel a small droplet of melt against a clean rotating metal wheel to produce a brittle ribbon or thin sheet. The ribbons are pulverised to obtain powder. The powders may be cold pressed and sintered or consolidated and heal treated (E.J.Lavemia, J.D.Ayers, T.S.Srivatsan, International Materials Review, vol.37, No. 1, (1992), 1-44). Then it is extruded or rolled to make the material for final product.
Rapid solidification technique however, capital incentive and requires high skill of operation because:
(i) the cooling rate is very high (105 to 106) which is difficult to achieve unless huge capital cost equipment is used, (ii) the powders / ribbons so obtained are not of uniform size leading to deterioration of mechanical properties, (iii) the steps of consolidation of the rapidly solidified alloy powders/ melt spin ribbons and processes to shapes give additional cost to the technique.(iv) the product capacity is limited to a small size only because the ribbon or powder so obtained are compacted or sintered to a small capacity for obtaining homogeneous structure
These necessitated R & D effbrts for development of Al-Fe-V-Si alloy in cast route whose mechanical properties are comparable with those of identical alloy made by the known process as mentioned above.
The process of present invention makes use of melting and alloying in a furnace. Castings are made in die casting or in permanent mould for ensuring a cooling rate 10°-50°C/s, which is common in foundry practices. The microstructure of the cast materials reveals massive ten-anned star shaped particles with composition similar to Al3Fe with some amount of V and Si along with other intei dendritic Al-Fe-silicide phases. These star shaped particles may act as notches, which are deleterious to the toughness of the materials. Moreover, the chunky star shaped particles prevent proper feeding of the casting which results in microporosity in castings. Thus, the mechanical properties of the samples deteriorate to a greater extent.
This invention aims to modify blocky primary inlermelallic phases as well as interdendritic silicide phases by treating the melt with elemental magnesium or magnesium beating master alloys to gel a structure containing uniform distribution of intemietallic phases. The uniform distribution of primary and interdendritic phases are obtained with addition of magnesium or magnesium beating master alloys because the moiphology of the inteiface changes, so more nuclei is created. It also breaks
the dendrite of the primary particles leading to structural change and fine particles,
The main object of the present invention is to establish melting treatment process for the production of cast and mechanically worked high strength and high wear resistant Al-Fe-V-Si alloys leading to superior properties.
Accordingly, the present invention provides an improved process fro the production of high strength and high wear resistant Al-Fe-V-Si alloys which comprises:
i) melting pure aluminum, Al-Fe-V, Al-Si master alloys at a temperature in the range of 800 to 1000°C to obtain a melt of Al-Fe-V-Si in the following compositional ranges:
Fe = 8 to 10 wt%, V=0.8 to 1.0wt%, Si=0.8 to 1.7 wt% and balance Al, ii) degassing the said melt by known method, iii) adding magnesium in the range of 0.05-1% to the degassed melt, iv) pouring the resultant melt in a dia/mould to obtain a casting followed by
cooling,
v) heating the casting obtained to a temperature in the range of 350-500°C, followed by hot rolling to obtain high strength and high wear resistant Al-Fe-V-Si alloys.
In an embodiment of the present invention the pure aluminum used may be of 99.6% purity.
In another embodiment of the present invention the degassing of the melt may be effected using known method such as adding known flux or argon gas.
In still another embodiment of the present invention the magnesium used may be such as pure magnesium of 99.8% purity.
In yet another embodiment of the present invention the magnesium used may be magnesium bearing master alloys such as Al-Mg, Fe-Si-Mg, Ni-Mg master alloys.
In another embodiment of the present invention the magnesium bearing master alloys used may be selected from Al-10-20%Mg, Fe-Si-9-20%Mg, Ni-10-20%Mg
The following example are given by way of illustration and should not be construed to limit the scope of invention.
Example 1
2 kg of Al-8.0% Fe-0.8% V -0.9% Si alloy was melted in a clay bonded graphite crucible in electric resistance furnace. The alloy was modified with 0.5% pure magnesium. The materials taken were metallic silicon 18 gm, ferro-vanadium 25 gm, aluminium- 30% iron master alloy 510 gm. 0.5% pure magnesium (10 gm) was used to modify the alloy. After melting the melt was kept at a temperature of 860° C for complete dissolution of solute elements. Degassing treatment was done by pure argon, followed by magnesium treatment at temperature of 850oC. The mell was poured in metallic mould of 30 mm diameter. The specimen so obtained was evaluated for microstructure and mechanical properties The microstructure was uniform distribution of primary and interdendritic phases in aluminium matrix. The mechanical properties were reported in Table 1
Table 1 Mechanical properties of unmodified and modified alloys
(Table Removed)Example 2
2 kg nf Al-8 0% Fe-0 8% V -0 9% ,Si alloy was melted in a clay bonded graphite crucible in electric resistance furnace. The melt was modified with 10% of aluminium-20% magnesium master alloy 20 gm of master alloy was taken The microstmeture obtained by this modification was more uniform distribution of primary and interdendritic phases The particle size distribution was finer than pure magnesium treatment The mechanical properties were shown in Table 1 The alloys were further hot rolled at a temperature of 350°C and deformation was 75% The mechanical properties was shown in Table 2.
Table 2 Mechanical properties of hot worked alloys, hot rolled at 350°C, reduction 75%
(Table Removed)Example 3
3 kg of aluminium -83% iron - 0 8% vanadium-0 9% silicon alloy was melled in a clay bonded graphite crucible in electric resistance furnace The alloy was modified with 1.0% of nickel - 20% magnesium. The materials taken were silicon 30 gm, ferro- vanadium 38 gm, aluminium - 10% iron master alloy 780 gm nickel- magnesium 30 gm After degassing the melt the alloy was modified. Prior to modification the master alloy was preheated to 250°C. The microstructure obtained by modification
was more unifonn distribution of primmy and interdendritic pliases The paiticle size distribution was finer than pure magnesium treatment The mechanical properties were shown in Table 1 The alloys were further hot rolled at a temperature of 350T and deformation was 75%. The mechanical properties was shown in Table 2
By the process of present invention a cast high strength and high wear resistant Al-Fe-V-Si alloy having unifonn distribution of primary phases in the form of ciiboidal, hexagonal, rectangular shape and refined interdendritic phase has been achieved The properties of the alloy produced by the process of present invention are comparable to those obtained through known process The mechanical properties also .improved considerably after hot working as shown in Table 1 and 2 above.
The main advantages of present invention are;
(i) The steps involved for making the alloy are simple, economic and takes much shorter time than the
existing process of rapid solidification route
(ii) Costly equipment for making powders/ ribbons are avoided in the process of present invention
(iii) Cooling rate required is much lesser than the existing process of rapid solidification
(iv) The process of present invention has achieved uniform distribution of refined primary intermetallic
and interdendritic silicide phases
(v) The cast and mechanically worked products produced by the present invention exhibit comparable
mechanical properties to those produced by rapid solidification processing route
(vi) The cost of production of the present invention is much cheaper than the existing process of rapid
solidification route.

We Claim:
1. An improved process for the production of high strength and high wear resistant
Al-Fe-V-Si alloys which comprises:
i) melting pure aluminum, Al-Fe-V, Al-Si master alloys at a temperature in the range of 800 to 1000°C to obtain a melt of Al-Fe-V-Si in the following compositional ranges:
Fe = 8 to 10 wt%, V=0.8 to 1.0 wt%, Si=0.8 to 1.7 wt% and balance Al, ii) degassing the said melt by known method, iii) adding magnesium in the range of 0.05-1 % to the degassed melt, iv) pouring the resultant melt in a dia/mould to obtain a casting followed by
cooling,
v) heating the casting obtained to a temperature in the range of 350-500°C, followed by hot rolling to obtain high strength and high wear resistant Al-Fe-V-Si alloys.
2. An improved process as claimed in claim 1 where in the pure aluminum used may
be of 99.6% purity.
3. An improved process as claimed in claims 1-2, wherein the degassing of the melt
is effected using known method such as adding known flux or argon gas.
4. An improved process as claimed in claims 1-3 wherein the magnesium used is
such as pure magnesium of 99.8% purity.
5. An improved process as claimed in claims 1-4 wherein the magnesium used is
magnesium bearing master alloys such as Al-Mg, Fe-Si-Mg, Ni-Mg.
6. An improved process as claimed in claims 1-5 wherein the magnesium bearing
master alloys used is selected from Al-10 to 20% Mg, Fe-Si-9 to 20% Mg, Ni-10
to 20% Mg.
7. An improved process for the production of high strength and high wear resistant Al-Fe-V-Si alloys substantially as herein describe with reference to the examples.

Documents:

448-del-1999-abstract.pdf

448-del-1999-claims.pdf

448-del-1999-correspondence-others.pdf

448-del-1999-correspondence-po.pdf

448-del-1999-description (complete).pdf

448-del-1999-form-1.pdf

448-del-1999-form-19.pdf

448-del-1999-form-2.pdf

448-del-1999-form-3.pdf

448-del-1999-petition-138.pdf

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Patent Number

197385

Indian Patent Application Number

448/DEL/1999

PG Journal Number

41/2007

Publication Date

12-Oct-2007

Grant Date

08-Oct-2007

Date of Filing

19-Mar-1999

Name of Patentee

COUNCIL OF SCIENTIFIC AND INDUSTRIAL RESEARCH

Applicant Address

RAFI MARG, NEW DELHI-110001, INDIA.

Inventors:

#	Inventor's Name	Inventor's Address
1	CHITTUR SUBRAMANIAN SIVARAMA KRISHNAN	NATIONAL METALLURGICAL LABORATORY, JAMSHEDPUR, BIHAR, INDIA.
2	KANAI LAL SAHOO	NATIONAL METALLURGICAL LABORATORY, JAMSHEDPUR, BIHAR, INDIA.

PCT International Classification Number

C22C 33/04

PCT International Application Number

N/A

PCT International Filing date

PCT Conventions:

#	PCT Application Number	Date of Convention	Priority Country
1			NA